Rotary piston engines

ABSTRACT

A multiunit arrangement of rotary piston engines has a threesection eccentric shaft. Each section of the shaft is driven by a rotary piston engine and one end of each section is an interference fit within the adjacent end of the neighboring section.

United States Patent inventor John Sharples Cheshire, England 86 1,8 12

Sept. 29, 1969 Nov. 16, 197 1 Rolls-Royce Limited Derby, England Oct. 2, 1968 Great Britain 46,739/68 Appl. No. Filed Patented Assignee Priority ROTARY PISTON ENGINES 7 Claims, 5 Drawing Figs.

U.S.Cl 418/210 Int.C1 .F0lc11/00, F04c 11/00 Field of Search 418/60, 212,213,210;91/411A;92/151;285/381 [56] References Cited UNITED STATES PATENTS 227,307 5/1880 Seelye 418/212 1,271,377 7/1918 Shiner 418/60 2,564,670 8/1951 Bratt 285/381 X 3,240,423 3/1966 Jones... 418/60 3,302,623 2/1967 Zimmermann 418/60 X 3,359,952 12/1967 Jones etal. 418/60 3,494,640 2/1970 Coberly et a1. 285/381 X FORElGN PATENTS 893,312 10/ 1959 Great Britian Primary ExaminerMartin P. Schwadron Assistant Examiner-Irwin C. Cohen Attorney-Cushman, Darby & Cushman ABSTRACT: A multiunit arrangement of rotary piston en gines has a three-section eccentric shaft. Each section of the shaft is driven by a rotary piston engine and one end of each section is an interference fit within the adjacent end ofthe neighboring section.

PATENTEnuuv 16 Ian SHEET 1 0F 3 r iana A Home y s PATENTEnuuv 16 ml SHEET 2 [IF 3 A Home y '1 ROTARY PISTON ENGINES The invention concerns improvements in or relating to rotary piston engines.

According to the present invention there is provided a multiunit arrangement of rotary piston engines having a shaft; at least two sections constituting said shaft one section being drivingly connected to each engine; mating surfaces on the ends of adjacent sections so that said adjacent sections are an interference fit; passageway means in said shaft for feeding a fluid under pressure to said mating surfaces so that the interference fit between adjacent sections is reduced by the fluid under pressure to permit assembling and disassembling of adjacent sections and; aligning means in the end of adjacent sections for locating each section of the shaft relative to the adjacent section.

Each section of the shaft may have an eccentric portion and a journal portion. Each journal portion thus may be located in annular fixed structure forming the casing of the engines. Preferably the fixed structure carries an externally toothed gear ring adapted to mesh with an internally toothed gear ring carried by the rotary piston.

Preferably each section of the shaft has a central bore and has securing means passing therethrough to locate the sections fixedly relative to each other.

The aligning means may comprise dowels fitted into holes provided in the end faces of each section of the shaft.

Preferably the ends of each section are tapered.

In one embodiment the externally toothed gear ring is provided with a flange which extends axially between said fixed structure and the ends of each said section.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which:

FIG. 1 is a longitudinal section taken through the shaft of a three-unit arrangement of rotary piston engines.

FIG. 2 is an enlarged section of a part of the arrangement shown in FIG. 1,

FIG. 3 is a modification of a part of the arrangement shown in FIG. 1

FIG. 4 is a still further modification of a part of the arrangement shown in FIG. 1, and

FIG. 5 is an additional modification of a part of the arrangement shown in FIG. 1.

Referring first to FIG. 1 there is shown a bank or multiunit arrangement of identical rotary piston engines designated by I, II, III, respectively. Since each is identical it will suffice to only discuss one in detail and its connection with its neighbor. The rotary piston engines are, in the present case, internal combustion engines but it will be appreciated that the present invention is applicable to any rotary piston engine e.g. a compressor or pump.

Piston engine II has a cylinder in which a rotating piston part of which is indicated at 10:: moves. The rotating piston may be any suitable shape but preferably for an internal combustion engine is of substantially triangular shape, the cylinder 10 being of a two-lobed substantially epitrochoid shape. The planetary motion of the rotating piston is preferably controlled by gearing which comprises a stationary externally toothed gear ring 9 rigidly connected to an engine casing 11, and an internally toothed gear ring 9a (only one of which is shown) rigidly connected to the rotating piston, the internally toothed gear ring rolling on the externally toothed gear ring 9 thus producing the planetary motion of the rotating piston.

The stationary gear has passing therethrough an eccentric shaft section 12, rotating about an axis XX, the shaft having end portions 13 and 14. The portion 14 journals the shaft section in the casing. The portion 13 is so dimensioned as to be an interference fit within the portion 14 of the adjacent eccentric shaft section 12.

The force required to drive the portion 13 into the portion 14 is reduced by forcing oil under pressure between the mating surfaces so that these surfaces are separated by a thin film of oil. The mating surfaces are tapered, thus improving the interference fit.

The oil for this purpose is pumped by a pump (not shown), through a plurality of drillings 15 in the shaft section 12, during the assembly or disassembly of the engine shaft to an annular groove 16 in the portion 13. Thus the oil is squeezed between the mating surfaces and on release of the pressure causing it to be fed to. the mating surfaces returns back to the pump.

The shaft sections of piston engines I, II and III are drawn together during assembly of the engine shaft or restrained during dismantling of one or more of the engines by a bolt 21a shown in phantom lines passing through a central bore 21 in the shaft sections.

The central bore also supplies lubricating fluid to the engine bearings by way of conduits 22, 23. Conduit 22 feeds lubricating fluid to an engine shaft bearing 24 and conduit 23 feeds lubricating fluid to the other engine bearings (not shown).

The externally toothed gear ring 9, disposed parallel to the shaft section 12 and having gear teeth 25, is affixed to the casing 11 by means of bolts 26 passing through an integral radial projection 27 from the gear ring into the casing.

It will be appreciated that the correct phase relationship must be maintained between the rotating pistons of engines I, II and III and thus there must be little or no relative movement between the eccentric shaft section 12 of each engine once the correct phase relationship has been set up. The interference fit between the shaft sections prevents such relative movement.

One arrangement to simplify angular positioning of the cccentric shaft sections on assembly is shown in FIG. 2. An end portion 30 of an eccentric shaft section (not shown) is fitted within an end portion 31 of an adjacent shaft section (also not shown). The two portions are located in their correct axial and angular positions relative to each other by means of a distance piece 33 carrying dowels 34. The distance piece 33 and the associated dowels are fitted into holes 35 and 36 in the portions 30 and 31 respectively.

The length of the distance piece 33 can be adjusted to limit the extent to which the adjacent portions are driven together thus simplifying assembly and ensuring that the required torque can be transmitted by the shaft. The dowels 34 located in holes 35 and 36 fix the angular relationship of one shaft section relative to the other.

FIGS. 3 and 4 show, in detail, the fixing of the externally toothed gear ring 9 to the casing 11. The parts similar to those shown in FIG. 1 have been designated with the same reference numerals. In FIG. 3 the gear ring 9 is fixed to a radial projection 27, which are separate from each other, by welding along the radially extending line 40. Alternatively as shown in FIG. 4, the gear ring 9 and the radial projection 27 are welded along the axially extending line 41. In both cases the projection 27 is bolted to the casing 11 by means of bolts 26. The welding may be of any conventional type although electron beam welding techniques ensure that distortion of the gear teeth 25 is kept to a minimum.

FIG. 5 shows a different arrangement for connecting the externally toothed gear ring 9 to the casing 11. In this case the gear ring 9 extends the whole axial extent of the casing 11 and has an integral flange 45 situated at the end remote from the gear teeth 25. The flange 45 is affixed to the casing 11 by means of bolts 46. Thus the internal surface 47 of the gear ring 9 forms the bearing surface between itself and the portion I4 and lubricating fluid is fed in the manner described with reference to FIG. 1 to a space 48 therebetween.

I claim:

1. A multiunit arrangement of rotary piston engines com prising at least two rotary piston engines having an interconnecting shaft means; at least two sections constituting said shaft means with one section being drivingly connected to each engine; mating surfaces on the ends of adjacent sections defining an interference fit; passageway means in said shaft means for feeding a fluid under pressure to said mating surfaces so that the interference fit between adjacent sections is reduced by the fluid under pressure to permit assembling and disassembling of adjacent sections and; aligning means in the end of adjacent sections for locating each section of the shaft means relative to the adjacent sections, said aligning means comprises circumferentially spaced dowel rods fitted into holds provided in end faces of each section of the shaft means.

2. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which each section of the shaft means has an eccentric portion and a journal portion.

3. A multiunit arrangement of rotary piston engines as claimed in claim 2 in which each journal portion is located in an annular fixed structure forming the casing of the engine.

4. A multiunit arrangement of rotary piston engines as claimed in claim 3 in which the fixed structure carries an externally toothed gear ring meshing with an internally toothed gear ring carried by the rotary piston.

5. A multiunit arrangement of rotary piston engines as claimed in claim 4 in which the externally toothed gear ring is provided with a flange which extends axially between said fixed structure and the ends of each said section.

6. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which each section of the shaft means has a central bore and has securing means passing therethrough to locate the sections fixedly relative to each other.

7. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which the ends of each section are tapered. 

1. A multiunit arrangement of rotary piston engines comprising at least two rotary piston engines having an interconnecting shaft means; at least two sections constituting said shaft means with one section being drivingly connected to each engine; mating surfaces on the ends of adjacent sections defining an interference fit; passageway means in said shaft means for feeding a fluid under pressure to said mating surfaces so that the interference fit between adjacent sections is reduced by the fluid under pressure to permit assembling and disassembling of adjacent sections and; aligning means in the end of adjacent sections for locating each section of the shaft means relative to the adjacent sections, said aligning means comprises circumferentially spaced dowel rods fitted into holes provided in end faces of each section of the shaft means.
 2. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which each section of the shaft means has an eccentric portion and a journal portion.
 3. A multiunit arrangement of rotary piston engines as claimed in claim 2 in which each journal portion is located in an annular fixed structure forming the casing of the engine.
 4. A multiunit arrangement of rotary piston engines as claimed in claim 3 in which the fixed structure carries an externally toothed gear ring meshing with an internally toothed gear ring carried by the rotary piston.
 5. A multiunit arrangement of rotary piston engines as claimed in claim 4 in which the externally toothed gear ring is provided with a flange which extends axially between said fixed structure and the ends of each said section.
 6. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which each section of the shaft means has a central bore and has securing means passing therethrough to locate the sections fixedly relative to each other.
 7. A multiunit arrangement of rotary piston engines as claimed in claim 1 in which the ends of each section are tapered. 